Push-type centrifuge



Aug. 23, 1966 E. RUEGG PUSH-TYPE CENTRIFUGE Filed May 10, 1963 INVENTOR. Erns'l Riiesg United States Patent 3,268,083 PUSH-TYPE CENTRIFUGE Ernst Ruegg, Kusnacht, Switzerland, assignor to Escher Wyss Aktiengesellschaft, Zurich, Switzerland, a corporation of Switzerland Filed May 10, 1963, Ser. No. 279,452

Claims priority, application Switzerland, June 4, 1962,

4 Claims. (Cl. 210-376) I This invention relates to a push-type centrifuge, with a centrifugal drum having screen holes and a pusher plate axially reciprocable relative to said drum, the centrifugal material being pushed stepwise over the inner surface of the drum by means of the annular push surface of said plate.

In these push-type centrifuges, the centrifuged material is brought on to the inner surface of the drum between the inlet funnel and the push surface on the front of the pusher plate, and is moved on said inner surface towards the outlet end of the drum. On the way through the centrifugal drum, liquid is continuously separated through the screen holes, so that the material being centrifuged becomes increasingly drier.

Since the centrifuged material forms a stiffer layer, that is to say one which is more pushable, the drier it is, the still very wet part of the layer situated immediately in front of the push surface is decisive for the possible throughput of centrifuged material through the push-type centrifuge. The throughput must be slow enough for the said wet part of the layer to have sufiicient time for the discharge of liquid so that the necessary stiffness, i.e. pushability, will be attained. This limits the performance of the centrifuge.

It is the object of the invention to improve the pushtype centrifuge in this respect. In a push-type centrifuge of the kind hereinbefore described, for this purpose according to the invention, the pusher plate, at least in the outer part of the region of its push surface, has screen holes for the discharge of liquid issuing from the centrifuged material.

constructional examples of the subject of the invention are represented in simplified manner in the drawing, wherein:

FIG. 1 shows a vertical axial section through a pushtype centrifuge.

FIG. 2 shows a part of FIG. 1 on a larger scale.

FIG. 3 shows a part corresponding to FIG. 2 of another embodiment.

The push-type centrifuge shown in FIGS. 1 and 2 has a housing 1, in which is journalled a sieve drum formed by a centrifugal drum 3 provided with screen holes 2. Mounted in the centrifugal drum 3 is a reciprocable pusher plate 4 having an annular push surface 5, by means of which the centrifuged material is pushed stepwise over the inner surface 6 of the drum. The supply of material to be centrifuged is 'by means of a pipe 7 and an inlet funnel 8. At the open outlet end of the centrifugal drum 3 is mounted a collector 9 for the discharge of the dried solid material. The separated liquid is collected in troughs 10.

The pusher plate 4 has in its push surface screen holes 11 for the discharge of the liquid issuing from the centrifuged material.

In this way, the discharge of liquid from the part P 3,268,083 Ce Patented August 23, 1966 of the layer of material being centrifuged situated between the pusher plate 4 and the inlet funnel 8 is very substantially accelerated, since in addition to the screen holes in the centrifugal drum the screen holes in the pusher plate, which occupy an approximately equally large area, serve for the discharge of liquid. In accordance with the acceleration of the discharge of liquid, the throughput of centrifuged material through the centrifuge can be substantially increased.

In the constructional example, screen holes are provided over the entire region of the push surface. The screen holes may also be restricted, however, to the outer part of the annular push surface.

The screen holes 11 of the push surface 5 are located in a screen 12 mounted on the front of the pusher plate 4 and resting on webs 13 of the pusher plate 4. The webs 13 leave free between each other liquid discharge chambers 14, and extend concentrically to the centrifugal drum 3. The faces of the webs 13 which are turned towards the axis of the drum define annular collecting troughs 15 for the liquid issuing from the screen 12. These collecting troughs 15 have an end which is more remote from the drum axis than the trough walls. Radial discharge Openings 16 are provided in the bottom of the collecting troughs. Liquid ducts, that is to say bores 17, lead the liquid to the back of the pusher plate 4.

In the embodiment shown in FIG. 3, a pusher plate 18 is provided with a frusto-conical push surface 19, which diverges in the direction toward the open outlet end of the centrifugal drum.

Mounted on the back of the pusher plate 18 is a device which discharges part of the liquid issuing through the pusher plate away from the pusher plate in the axial direction of the centrifugal drum. This device has an axially projecting guide ring 20 which is mounted in the vicinity of the pusher plate periphery, rigidly secured to the pusher plate 18, and forms a pointed cone. The liquid flowing over the guide ring is always supplied to a part of the centrifugal drum which is less loaded with liquid. In addition, the guide ring prevents the liquid issuing from the ducts 21 of the pusher plate 18 from impinging directly on the surface of the centrifugal drum.

What is claimed is:

1. In a push-type centrifuge of the type including a rotary, foraminous drum having an open end, and a reciprocable pusher plate having an outer annular portion, that portion being arranged to move material to be centrifuged stepwise along the foraminous drum toward said open end, the improvement which comprises a screen mounted on the front of the outer annular portion of the pusher plate; and annular webs forming said outer annular portion of the plate and supporting said screen, said we'bs defining concentric annular discharge chambers for liquid separated from the material to be centrifuged, each chamber including a drainage duct extending through said outer annular portion, and ducts serving to distribute the separated liquid longitudinally along the foraminous drum.

2. The push-type centrifuge defined in claim 1 in which the outer annular portion is of frusto-conical shape diverging in the direction toward the open end of the foraminous drum.

3 4 3. The push-type centrifuge defined in claim 1 which References Cited by the Examiner comprises means for leading the liquid discharged on the rear side of the pusher plate away therefrom in the axial UNITED STATES PATENTS direction 2,232,770 2/1941 Buddeberg 210-376 X 4. The push-type centrifuge defined in claim 3 in which 5 3,136,721 6/1964 Gooch 210376 said means for leading the liquid away from the pusher plate comprise an axially p projecting guide ring REUBEN FRIEDMAN, Primary Examiner. connected to the rear side of the pusher plate adjacent its outer periphery. I. DECESARE, Assistant Examiner. 

1. IN A PUSH-TYPE CENTRIFUGE OF THE TYPE INCLUDING A ROTARY, FORAMINOUS DRUM HAVING AN OPEN END, AND A RECIPROCABLE PUSHER PLATE HAVING AN OUTER ANNULAR PORTION, THAT PORTION BEING ARRANGED TO MOVE MATERIAL TO BE CENTRIFUGED STEPWISE ALONG THE FORAMINOUS DRUM TOWARD SAID OPEN END, THE IMPROVEMENT WHICH COMPRISES A SCREEN MOUNTED ON THE FRONT OF THE OUTER ANNULAR PORTION OF THE PUSHER PLATE; AND ANNULAR WEBS FORMING SAID OUTER ANNULAR PORTION OF THE PLATE AND SUPPORTING SAID SCREEN, SAID WEBS DEFINING CONCENTRIC ANNULAR DISCHARGE CHAMBERS FOR LIQUID SEPARATED FROM THE MATERIAL TO BE CENTRIFUGED, EACH CHAMBER INCLUDING A DRAINAGE DUCT EXTENDING THROUGH SAID OUTER ANNULAR PORTION, AND DUCTS SERVING TO DISTRIBUTE THE SEPARATED LIQUID LONGITUDINALLY ALONG THE FORAMINOUS DRUM. 